External defibrillators (“EDs”) are emergency medical devices designed to supply a controlled electric shock (i.e., therapy) to a person's heart during cardiac arrest. This electric shock is delivered by pads that are put into contact with the person's body.
During a cardiac arrest, the heart loses its normal electrical rhythm, commonly referred to as cardiac arrhythmia, and may adopt a fibrillation or tachycardia rhythm. As a result, the heart is unable to pump blood properly through a person's body. Unless a timely rescue attempt using an ED is made to restore the normal electrical rhythm, death can result.
To provide a timelier rescue attempt for a person experiencing cardiac arrest, some EDs have been made portable and have been designed to be operated by non-medical personnel. These portable EDs (PEDs) have gained acceptance by those outside the medical profession and have been deployed in myriad locations outside of traditional medical settings. Due to the life saving benefits of PEDs, more and more non-medical users are purchasing and deploying PEDs in their respective environments. This allows for a rescue attempt without the delay associated with bringing the person to a medical facility, or bringing a medical facility to the person (e.g., a life support ambulance).
Individuals as well as businesses are purchasing and deploying PEDs. As time is of the essence during any rescue attempt, multiple PEDs may be purchased by any particular individual or user to allow placement at multiple locations. In the case of an individual, this could be on several floors of a home, and in the case of a business, this could be for placement throughout a facility (e.g., factory, office building, or large retail center). Thus, regardless of where the victim is within the home/facility, access to a PED would only be seconds, or minutes, away.
Many of these deployed PEDs rely on battery power. More specifically, they use a battery as their primary source of power and are stored disconnected from a power grid (e.g., the battery is not constantly being charged). As these PEDs are standby devices that are used infrequently, typically a PED will remain in storage for long periods of time until, if ever, called upon to perform a rescue attempt.
Battery powered PEDs have a fixed battery life (e.g., the batteries must be recharged or replaced after some interval of time). Typically, battery life is measured in terms of months or even years. Minimizing power consumed (i.e., battery drain) by the PED while in storage to maximize PED availability is critical for a rescue attempt. More specifically, battery life is determined by two main factors, battery aging and battery usage. Battery aging results from the ongoing chemical reaction taking place in the battery, thus sets the maximum battery life possible. Battery usage, however, is due to such factors as tasks the PED must perform during storage to assure proper functioning, such as simple maintenance checks, and shortens battery life. It should be appreciated that regardless of the reason, a battery will lose power over time. Unfortunately, if the battery is not serviced there will come a point in the life of a PED where the PED will be unable to provide the necessary life saving shock during a rescue attempt due to a low battery condition.
In addition to battery life issues, PEDs may also have other issues. As mentioned above, the battery may provide power for performing maintenance checks to assure proper functioning. It is thus always possible that the PED may have a maintenance issue that requires action to allow the PED to function properly.
As a result of battery life issues and maintenance issues, a PED may require both scheduled maintenance (e.g., battery replacement) and unscheduled maintenance to assure that it is always ready to provide its life saving therapy when called upon.
To this end, PEDs incorporate various sensory alerts (i.e., devices that the senses (such as eyes or ears, can detect) to notify a user when maintenance is needed. For example, a PED may incorporate mechanical means, such as a status indicator (e.g., a flag that changes colors—from green (i.e., in service) to red (i.e., maintenance needed, or out-of-service)). These types of passive sensory alerts have the benefit of being very low power, but are subtle and can easily be missed, such as when the PED is not stored in plain sight (e.g., in a closet), or in low lighting. Active sensory alerts, such as an auditory (e.g., beeping alarm) or visual (e.g., a flashing light), provide a more noticeable signal, but use much more power.
It should be appreciated that sensory alerts are ideally provided before the PED reaches the point where it cannot function in a rescue attempt, but must be provided when the PED is no longer capable of performing a rescue attempt. It should also be appreciated that sensory alerts, particularly of the active types, depending upon their robustness can use significant battery power. Thus, there is a tradeoff between power usage for sensory alerts that command attention, and retaining power for a rescue attempt. In the most extreme and undesirable situation, a sensory alert meant to indicate simply a need for maintenance to preserve an existing rescue attempt capability (e.g., a low but usable battery) could actually drain sufficient power from the PED battery so the PED would not be able to perform a rescue attempt.
In the rigid and controlled medical environment, PEDs are constantly monitored and checked to assure the PED's operational status, thus low subtle sensory alerts are effective. However, in the less rigid and uncontrolled non-medical environment, the robustness of the sensory alert needed to assure action may use a significant amount of power. Thus, there is a need in the art for a more effective method of monitoring PEDs and alerting those in charge of the PED's maintenance when a PED is in need of maintenance to assure that it is ready to support a rescue attempt when called upon to do so.